On board the USS Minnesota, in action during the assault on Fort Fisher, 15 January 1865. Landing on the beach with the assaulting party from his ship, Mills charged up to the palisades and, when more than two_thirds of the men became seized with panic and retreated on the run, risked his life to remain with a wounded officer. With the enemy concentrating his fire on the group, he waited until after dark before assisting the wounded man from the field.